Geo-engineering in vogue…

There was an interesting article in the NY Times this week on possible geo-engineering solutions to the global warming problem. The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC/ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and cool the planet – analogous to the natural effects of volcanoes. The paper is being published in Climatic Change, but unusually, with a suite of commentary articles by other scientists. This is because geo-engineering solutions do not have a good pedigree and, regardless of their merit or true potential, are often seized upon by people who for various reasons do not want to reduce greenhouse gas emissions. However, these ideas keep popping up naturally since significant emission cuts continue to be seen as difficult to achieve, and so should be considered fairly. After all, if there was a cheaper way to deal with the CO2 problem, or even a way to buy time, shouldn’t we take it?

First a little history [Update: See Spencer Weart’s essay on the history of climate modification ideas]. Geo-engineering ideas first reached the public in the 60s when there was still a lot of enthusiasm for technical fixes of the world’s problems. One example was suggested by the Soviets who wanted to melt the Arctic (either using soot or nuclear devices) in order to warm up their frozen North. More recently, there was a proposal to dam the Straits of Gibraltar in order to prevent more saline Mediterranean Sea water (because of the Aswan Dam) from affecting the North Atlantic conveyor circulation (no, it didn’t make sense to us either). With such a pedigree, geo-engineering is generally seen as fringe entertainment at best, although some of the new ideas concerning atmospheric carbon dioxide sequestration are being looked into seriously.

Edward Teller is the scientist most associated publicly with the idea of creating a stratospheric shield to prevent excessive global warming, though he built on an idea from Freeman Dyson (who has subsequently become a bit of global warming contrarian)*. However, as Teller’s collaborator Stanislaw Ulam once said after discussing some new ideas with him: “Edward is full of enthusiasm about these possibilities; this is perhaps an indication they will not work”. And given Teller’s estrangement from the scientific community in his later years, it was not likely that the concept would be taken very seriously, and indeed it hasn’t been.

But now Paul Crutzen has stepped into the fray. He has a much more solid reputation amongst climate scientists than Teller, and thus his ideas will be taken more seriously. I haven’t seen the new paper yet (it’s out in August) but there are a number of questions that need to be addressed before any geo-engineering proposal combatting global warming should be thought of as anything more than an interesting idea. First, the idea has to actually work, second, the side effects need to be minimal, and third, it has to be able to keep up with an increasing forcing from ever higher greenhouse gas levels, and fourth, it has to be cheaper than the simply reducing emissions at source. These are formidable hurdles.

Would it work? In most of the cases under discussion the target is the global mean temperature, and so something that balances the global radiative forcing of greenhouse gas increases is likely to ‘work’. However, having no global mean forcing is not the same as having no climate change. A world with higher GHGs and more stratospheric aerosols is not the same as a world with neither.

Thus there will be side effects. For the stratospheric sulphate idea, these fall into two classes – changes to the physical climate as a function of the changes in heating profiles in solar and longwave radiation, and chemical and ecological effects from the addition of so much sulphur to the system. Physically, one could expect a slight decrease in surface evaporation (a ‘dimming’ effect) and related changes to precipitation, a warming of the tropopause and lower stratosphere (and changes in static stability), increased Eurasian ‘winter warming’ effects (related to shifts in the wind patterns as are seen in the aftermath of volcanoes). Chemically, there will be an increase in ozone depletion (due to increases in heterogeneous surface chemistry in the stratosphere), increases in acid rain, possibly an increase in high cirrus cloud cover due to indirect effects of the sulphates on cloud lifetime. Light characteristics (the ratio of diffuse to direct sunlight) will change, and the biosphere may react to that. Dealing with the legal liability for these predictable consequences would promise to be a lively area of class action litigation…. On the positive side, sunsets will probably be more colorful.

Could it keep up? GHGs (particularly CO2) are accumulating in the atmosphere and so even with constant present-day emissions, the problem will continue to get worse. Any sulphates put in the stratosphere will only last a couple of years or so and need to be constantly updated to maintain concentrations. Therefore the need for the stratospheric sulphates will continue to increase much faster than any growth of CO2 emissions. This ever-increasing demand, coupled with the impossibility of stopping once this path is embarked upon is possibly the biggest concern.

How expensive would it be? I will leave the detailed costing to others, but stemming from the last point, the cost will continue to rise indefinitely into the future unless this proposal is coupled with an concomitant effort to reduce CO2 emissions (and concentrations) such that the need for the sulphates will diminish in time.

Crutzen’s paper may well address these issues comprehensively (and I look forward to seeing it) but, in my opinion, the proposals are unlikely to gain much traction. Maybe an analogy is useful to see why. Think of the climate as a small boat on a rather choppy ocean. Under normal circumstances the boat will rock to and fro, and there is a finite risk that the boat could be overturned by a rogue wave. But now one of the passengers has decided to stand up and is deliberately rocking the boat ever more violently. Someone suggests that this is likely to increase the chances of the boat capsizing. Another passenger then proposes that with his knowledge of chaotic dynamics he can counterbalance the first passenger and indeed, counter the natural rocking caused by the waves. But to do so he needs a huge array of sensors and enormous computational resources to be ready to react efficiently but still wouldn’t be able to guarantee absolute stability, and indeed, since the system is untested it might make things worse.

So is the answer to a known and increasing human influence on climate an ever more elaborate system to control the climate? Or should the person rocking the boat just sit down?

270 Responses to “Geo-engineering in vogue…”

At my workplace lunchroom there is one of those cartoon-a-day desk calendars, only this one is a collection of proverbs from many cultures. The one for tomorrow (4 July) is interesting when thinking about people arguing that global warming has a “big project” solution:

And once you figure out that problem, you can try estimating the likely impact of that warm, unstratified ocean on marine phytoplankton primary productivity that currently provides about 40-50% of our atmosphere’s oxygen.

Below I have responded to some of the comments related to the Times article and the subject of geoengineering. I coauthored the plan to cover the deserts with white plastic and was quoted in the article. I also want to point out that many of the proposed solutions mentioned in the article have been discussed elsewhere in a kind of periodic reinventing of the wheel process that seems to have occurred every few years since the mid 1980’s when the problem of global climate change first began to be taken seriously. See the links and books below for a pretty thorough coverage of the topic.

What is significant about the Times article to me is that Dr. Ralph Cicerone, president of NAS is now back on the side of promoting research in this area. Like so many scientists involved with the climate change problem, he has been to say the least, conflicted on the idea of geoengineering. In the early 90s he proposed and later changed his mind about a plan to inject large quantities of hydrocarbon gases into the stratosphere to solve the ozone depletion problem. Later in the decade, he came out against doing any geoengineering work. So for him to do a 180 on this along with Paul Crutzen picking up the Teller ball and starting to run either indicates we have reached a tipping point of sorts for geoengineering or the end of another cycle of debate on the issue.

For anything useful to come out of a debate on geoengineering, there must be serious research funding. I would doubt that more than $25 million has been spent in total since 1980 in government, academic and industry studies, hardly enough to answer any questions. The main funding agencies in the U.S: DOE, EPA, NSF, NOAA and NASA probably spend a total of less than $1 million a year on this topic if that much and most of that goes into production of “what if” journal articles, not real engineering research.

Likewise, Stanford U. received or is supposed to receive $250 million from ExxonMobil, Toyota, GM and others to sponsor academic global warming research. One of the categories is geoengineering, but to date the funding in this area is zero.

Internationally, the Blair government in Britain sponsored a macro-engineering symposium in 2004, but nothing has come from that either.

Probably the best way to include geoengineering schemes is as part of a portfolio of options that include development of new energy technologies and others to reduce GHG emissions. Within that framework, the geoengineering technologies would not be responsible for offsetting all the GHG warming and their share would be dependent on how rapidly the emission reduction technologies can be deployed. For example, if total human GHG emissions are 10GtC/yr., a set of 3-5 different geoengineering technologies could be used to offset the warming due to 5GtC.

1. RE: 2 Geoengineering won’t address acidification of the oceans.

Not true if removal of CO2 from ambient air by sorbents or increased ocean phytoplankton biomass can be made possible. The prospects for either of these working are however, not likely at present. The good news is that the level of acidification that would bring an end to us won’t occur for several hundred years giving us somewhat more wiggle room than that from the warming.

2. RE: 5 Geoengineering should be considered a quick fix to abrupt climate change.

Referring to it this way or as an insurance policy as Ralph Cicerone did in the article is misleading. Insurance policies provide for some compensation after damage has occurred. They can’t prevent damage. Calling it insurance, however, may allay some concerns, i.e., we’ll develop it, but we will only use it if we have to.

The reality is that with the possible exception of the stratospheric injection of sulfate aerosols, none of the proposed geoengineering approaches can be deployed quickly. They would take decades and thus would best be used to offset warming year-over-year. Trying to reduce warming or even CO2 levels rapidly would not be a good idea and might cause an abrupt climate shift with consequences as bad as allowing the long term change to continue.

The best answer is to not let it go that far. If we wait until atmospheric temperatures are up 5-10F and then decide something has to be done because other feedback systems are kicking in, e.g., gas hydrate releases from permafrost or ocean sediments or the northern THC has shutdown due to melt water from Greenland, then all bets are off and we are about as well prepared as the scientists in a sci-fi movie who have to take some risky gamble to save mankind from certain doom.

Acid rain is a phenomenon related to coal fired power plant emissions whereby exhaust gases from towers several hundred feet high are blown across states and cause damage to lakes and trees. The emissions are somewhat concentrated in the form of plumes and are mainly in the lower troposphere. I am not aware of any acid rain damage from e.g., the eruption of Mt. Pinatubo, whose sulfate aerosols combined with dust from soil and rock associated with the eruption wound up in the stratosphere and cooled the atmosphere for about 1 year in the early 90s.

So it may be possible to use aerosol injection in the stratosphere without significant acid rain, since most of the rainout would occur over the oceans. Any other types of chemical reactions, especially those that might result in stratospheric ozone depletion would need to be known in advance. Hence, the need for some extensive research on this topic. Large volcanic eruptions on the scale of Mt. Tambora, the cause of the year without a summer in 1815 are too infrequent to worry about.

As to the call for an Energy Manhattan project, John Kerry and Roscoe Bartlett (Republican Rep. From MD and former college professor) have both called for such an effort, no doubt frustrated with the words without deeds approach of the present Administration: Clear Skies, Freedom Car, FutureGen, etc. They have cited the example of DARPA, which seems to always be at the cutting edge of engineering research, especially in robotics.

The reality is that we presently lack the ability to deliver and construct such large objects in space, either in low Earth orbit or at the L1 point, 900,000 miles from Earth. Likewise, for the proposals to place lots of little mirrors or diffractors in space. When that technology becomes available is uncertain, but it is unlikely to be available in time to stop the 21st century warming. Our difficulty with completing the International Space Station is testimony to present day launch capabilities that are now easily thwarted by such problems as spray-on insulation on the side of a fuel tank.

The LLNL modeling, limited though it was, showed that a reduction of solar radiation from outside the atmosphere would not result in hot or cold spots inside the atmosphere or on the surface. Intuitively that would make sense, since the solar radiation is being reduced uniformly.

5. RE 19, 26, 52, 72, 78, 98. Transferring surface heat of the ocean to the lower depths by artificially mixing seawater at the surface and at lower depths.

We lack the capability to do this. The amount of water that would have to be transferred is just too large. Any problems caused by doing this are therefore irrelevant.

6. RE 27 Release of engineered gases to neutralize GHG warming.

There are no gases that could do this. If it got too cold, however, we could release fluorinated carbon compounds that have enormous greenhouse warming potentials (another Crutzen idea picked up by the authors of the report for the Pentagon on Abrupt Climate Change as a means of offsetting a THC shutdown). Even I had some problems with that one.

The explanation is that these options don’t require a complete overhaul of the energy, land use and food production technology and practices of human civilization. Dr. Crutzen’s sulfate aerosol project could in theory be “off the ground” within, say 5 years. It will take decades to replace nearly a billion motor vehicles, 25,000 power stations and millions of home and industrial heating systems, once alternatives to the present technologies are found. Thus, the geoengineering schemes are independent of energy and other technologies and don’t have to wait for them to be perfected.

8. RE 40 Non acid rain producing particulates to reflect sunlight.

Inert materials like aluminum oxide could be used, but their residence time is much less than the aerosols and thus their effectiveness is limited.

A valid point and one debated at the highest levels of the U.S. government, believe it or not. The reality is that since we don’t have any GHG emissions reducing technologies and the time is drawing nigh to do something, better to stop the warming any way we can and hope the people who control the levers of power and money recognize that these are stop gaps and not solutions, designed to buy time and not a quick exit from the global warming problem.

10. RE 44: Size of the space reflector.

Around 2,000,000 square miles to offset warming due to a doubling of CO2 in low Earth orbit (200 miles up) and 1 million square miles at the L1 point, 900,000 miles from Earth. How doable does that sound?

11. RE 45. Developing geoengineering capability will help us control the Earth’s climate and prevent future ice ages, etc.

One theory has it that the introduction of man-made GHGs has prolonged the interglacial. Regardless, if we are going to continue to live on this planet and colonize other worlds, at some point controlling and manipulating the climate to prevent an ice age or for purposes of terraforming will become necessary.

12. RE 50. Industry will buy desert land in advance of coverage with white plastic or other material. What about local geoengineering?

We determined that the only way that land coverage could be done cost effectively is if the land use were either donated in return for emission reduction credits for those countries who could afford to pay (Libya, Saudi Arabia, etc.) and in return for debt forgiveness for those with lots of international debt (Mauritania, Mali, etc.).

As to targeted geoengineering, there has been some discussion among the geoengineering community (barely enough people to hold a decent 4th of July barbecue) to do some things along these lines.

One example is to slow down the melting of the Greenland ice cap by placing insulating covers over the nascent streams that now criss-cross the glaciers (visible in the Gore movie). The water in these wannabe rivers has cut channels all the way to the bedrock and now drains out into the Atlantic. Just like the open ocean water in the Arctic during the summer, the blue water accelerates the melting.

One concern is that if enough of these melt water channels combine, a large lake could be created and if it grew large enough and the water from it were suddenly released into the Atlantic, the northern THC might be disrupted, similar to what happened when Lake Agassiz in the area now occupied by the Great Lakes emptied into Hudson Bay and ultimately the N. Atlantic some 12,000 and 8000 years ago.

To prevent either this or the more likely scenario of the gradual melting of the ice cap, coverage of the open water there could slow it down. Likewise, snowmaking machines could be used to fill in the cracks with ice during the winter. Finally, we have looked at selective coverage of parts of the SW Sahara to disrupt the formation of Atlantic hurricanes.

As to the last comment about relieving the pressure on the Caldera super volcano in Yellowstone, we lack the technology to have any impact on that situation.

13. RE 51. Too much uncertainty to ever attempt geoengineering of the climate.

A lot of the uncertainty about this and other technologies will eventually go away as we learn more. Funding of research is one way for that knowledge base to be acquired. Whether individuals are strongly in favor or opposed to technologies generally has no bearing on their development and application, even among the developers. Look at nuclear weapons and genetically engineered crops. Has anybody from the government asked what you think about FutureGen or carbon capture and sequestration, two large government programs that ARE being funded?

14. RE 53 Run jet aircraft at rich fuel to air ratio to produce more soot or use high sulfur fuel.

The comment only mentioned the use of high sulfur fuel, but both have been discussed before. Again, not enough is known of the impacts. Planes also only spend some of their time in the air at or around the stratosphere.

All three of these ideas have been discussed before. The sorbent research is now being conducted by Klaus Lackner at Columbia U. The problem is that the sorbent requires too much energy to be regenerated, even with a self- generating airflow as is also proposed. Ideas proposed in the 80s called for replacing the fossil energy costs of ambient air CO2 extraction systems by building nuclear or solar plants to provide their energy. So much energy was required that it made more sense to simply generate all the electricity from solar or nuclear and forget the ambient extraction.

White plants in the desert sounds good, but the water and fertilizer are an insurmountable problem. Covering the ocean is a bad and an impractical idea, since the material will block phytoplankton access to sunlight and will eventually turn brown or green from algae, rendering it useless for reflecting sunlight.

There are also very few people thinking about any geoengineering ideas. That’s one of the problems. And it’s the same people over and over again, myself included!

16. RE 77. Once you drink the geoengineering Kool Aid, you have to keep on drinking it.

The argument is that if we decide to go with the stratospheric aerosol injection scheme, if something causes us to have to stop like a war or other catastrophe and the CO2 levels are e.g., 700ppm, then there would be an abrupt climate change brought about by the sudden increase in radiative forcing. That’s correct for this and to a certain extent any of the other plans which aim to reduce solar radiation.

But realistically, we should have solved the energy and climate change problems by the end of this century. One hundred years is a long, long time at this stage of human civilization and one should not discount the impact of future technological developments, even though they may not help us out of the present situation for 50-75 years. Just as in the paper studies of high-level nuclear waste disposal (a report on options for dealing with this I wrote in graduate school in 1977 is regrettably still pretty valid), how many people actually believe we will have to safeguard the waste for hundreds of thousands of years? Thus, the geoengineering plans shouldn’t have to be employed for longer than 100 years from today to deal with our current climate change problem. Commenter 79 is on the right track, just a little too pessimistic, while 84 is probably too optimistic.

Pigments or other materials that emit in the IR also strongly absorb in the other solar wavelengths. Unless the IR emitted was in the atmospheric window, the IR would simply be absorbed by the GHGs on the way up. Deploying the pigmented material at night only to avoid the solar radiation would not be practical. Either way it won’t work, although that hasn’t stopped people from getting patents based on the concept: R.J. Parise, Anti-Global Warming Device, U.S. Patent Application 20010000577, May 3, 2001.

So until I see the majority of the population adopting measures of conservation I too will be in vocal opposition to any geo-engineering projects.

That’s just the problem. It’s like arguing with the fire department over whether their water will ruin your antiques as your house is burning down. We need to put out the fire (uncontrollably rising temperatures) first if we are serious about this at all.
Otherwise, this degenerates into an exercise in empty moral posturing. I think you’ll be waiting a long time, and by the time your conditions are fulfilled, it may be too late to matter. BTW, I am in the camp of those who addvocate geoenginnering as a way to buy time, not as a permanent solution.

Re 70:

The alcoholic analogy is ingenious but flawed in one major way. If the alcoholic falls off the wagon, he takes only himself down, If you depend completely on the public to solve GW immediately through conservation and insufficient nnumbers do so to make the difference, the whole world is taken down.

Re 85:

if a geo-engineering fix turns out not to work and ends up making the situation worse, will it be possible to repair the damage?

This is a common objection, but when we get down to specific schemes, we often find that there is ample reason to believe that no nightmare scenario will come to pass. In the case of the sulfate idea, we already have data concerning what will happen, courtesy of volcanic eruptions. The effects are short-term unless continuously renewed. If we don’t like the effect, we need only to stop doing it and the sulfates will be gone in a year or two.

Another thought: what would injecting ozone into the middle stratosphere do?

There’s a fourth real-world question that our Science Times story, with limited space, couldn’t address: Would an engineered solution to the greenhouse problem be done unilaterally by a country most threatened by warming or by international accord?

If unilateral, it could lead to conflict (think about the old Cold War weather modification notions). But if global consent was required, how in the world could anyone get the international community — which finds it hard to settle on a common approach to preventing a global environmental problem — to agree on something like dimming the sun with space mirrors or adding pollution to the atmosphere?

Where the US is concerned, global consent is not a condition of contemporary foreign or environmental policy.

It would be a stretch to imagine any planning, on the part of the US, to actually attempt to engineer a solution to the greenhouse problem because doing so would follow an acceptance of a unilateral threat by warming. At the time of accepting that threat is real, the warming train would be so far down the tack, time and money would rule out any geoengineering scheme (e.g., positive feedback from tundra and permafrost).

However, a one trillion dollar act of desperation might be proposed by politicians in the west and southwest — digging channels to divert Arctic runoff to the Colorado and Missouri Rivers to salvage America’s ag economy and Las Vegas’ “attractions”.

Its time to put the geoenginering discussion in the barn and get about serious business of addressing glacial melt in the tropics and the consequences for downstream populations.

You write above “… the level of acidification that would bring an end to us won’t occur for several hundred years …”

What’s your source for this statement, please? Do you have a pH level associated with that time span? Are you familiar with the work discussed here earlier?

Are you — or your source — focusing on levels that would directly cause “an end to us” (‘several hundred years’) as distinguished from the level (by 2100) when marine plankton can no longer form aragonite shells? If so, why?

A geoengineering response to climate change is one that the U.S. would seemingly embrace. It allows business as usual, and it is relatively inexpensive. It should be stressed that the Bush Administration acknowledges global warming, but does not want to take any action that would threaten economic consumption.

It is logical to assume that a geoengineering response to climate change has already been discussed in the private chambers of the U.S. government and with other governments of the world. In my view it is up to the climate science community to analyze the feasibility, risks, and effectiveness of geoengineering to offset the affects of rising concentrations of heat-trapping gasses.

“I think consumers should be able to buy whatever vehicle they want, but I would suggest that they have to pay the external costs up front when they buy a vehicle: i.e., up front fees for health care costs (asthma, etc.), DOD costs (fighting for oil), global warming costs (this is a more difficult one to estimate), and pollution costs (CO, Unburned HC, NOx, SOx). This would be like taking responsibility for your actions.”

I agree with the general principle here, that of accepting reponsibility for all of one’s actions. However, I think there are several problems with this:

1. We cannot determine all the upfront “costs.” Do we in the industrialized world now have to compensate people in the developing world because we’ve “used up” the resources (including CO2 capacity in the atmosphere)? That was an upfront cost that we did not pay, but have passed along to others.

2. People will not WANT to pay all the costs or accept responsibiility. This is the same generation that is passing along the costs of their pensions to their children. Americans (and Canadians) have developed a magical “something for nothing” mentality. Also, paying now will mean a different – not necessarily worse – standard of living.

3. We are deceiving ourselves if we think we have much individual freedom of choice. Our society is set up to quietly guide us in certain acceptable ways; that’s why violence in American movies is pervasive and widely accepted, but sexuality is frowned upon. It’s why we have zillions of miles of roads rather than rail lines – the former being paid for exclusively by the government.

In the U.S., everyone has the ‘choice’ whether or not to own a car. Realistically, however, government subsidies and industry lobbying have made living without a car very difficult for most. Because of the way our society and cities are configured, owning a vehicle means increased opportunities. If the price of cars were to truly reflect their “cost,” there wouldn’t be many cars. And how do you put a price on intangibles, like clean air, being able to talk on your porch without being drowned out by a Harley, and so on?

I think the U.S. car-based economy/landscape/lifestyle qualifies as geoengineering, and it hasn’t worked out well. As usual, unintended and unforeseen consequences were…unintended and unforeseen.

Any engineering study must include as many alternatives as possible and the related results of each. If we do nothing (skip through the daisies, stick out head in the sand, etc) what will be the result? We can model outselves into insensibility, predict ourselves silly and run anticipative programs until out computers burn but we will not know truly what will happen. What did happen in the past is probably a lot easier to examine with a great measure of reliability. We do know that around 900 AD until around 1400 AD we had a large warm spell on the planet. We don’t really need any science to know this for viking history tell us it was warm enough in Greenland to support 10,000 people in an agricultural society. We know when they got there, (Eric the Red) and when they left. We also know that it was too cold to live there anymore and still is. We also know that in many parts of the world there were societies which prospered at the same time which have been found in areas which are way too dry (since around 1350 – 1450) to support anywhere near the same number of people. I am sure the minds in this commentary could add several to the following: The Anasazi culture of SW United States, The Great Zimbabwe Culture of Zimbabwe, the Songhai culture of the upper bend of the Niger river, and (this will take some imagination) the Mongol Culture of the North edge of the Gobi. (Where did Temujin get the million soldiers and the millions of horses if there weren’t higher rainfalls for six or seven generations?)
The indications are that higher temperatures have historically produced more not less rain. We can also see that lower temperatures have demonstrably produced less water in the atmosphere. History says that higher temperatures will make the deserts bloom and the steppes lush; why don’t our models?

For starters I have very serious doubts about the efficacy of geo-engineered solutions to global warming.
I don’t believe we currently have the necessary knowledge to safely embark on any of the suggested solutions. If scientists and engineers will step up to the plate and categorically state that they have unequivocal proof that a specific solution will work without having catastrophic side effects then let them present their data and I’ll be willing to listen to their arguments. Heck in the mean time we can’t even seem to be able convince our home grown deniers that a problem exists that needs a solution, so how do you suppose we are going to get a global agreement on which solutions to try?

So what I really meant was that I’d like to see the engineering being focused much more on the conservation side for now. Before we start with seeding sulfate aerosols and building space mirrors to reflect solar radiation. I’d like to see some out of the box thinking down on the ground . It might mean I have to give up my car and ride an electric scooter to work while wearing an engineered breathable waterproof impact resistant fabric to keep me safe and comfortable from the elements. I might buy that tomorrow but I’m going to be very reluctant to put my money and support behind a large scale geo-engineering project.

I would much prefer to see the focus of engineering on ideas like that if possible on a massive global scale.
Maybe we also need some serious social engineering as well so it becomes less and less acceptable to emit greenhouse producing gases in the first place.

We live in a society that can market refrigerators to Eskimos (uh, given what is occurring that might not be a good example) but I suppose you get my point. So let’s start using that talent to change behavior on a global scale.

As for the alcoholic analogy I think it is comparing society at large as behaving like a drunk in denial not just any one individual. So we are talking about all of society functioning as a single entity therefore the analogy is valid in my opinion.

Those that manifest strong or unequivocal opposition to geoengineering before any serious study has been published or examined underestimate the serious danger our planet is facing. Right now CO2 is concentrated at 380 ppm in the atmosphere. At above 400 ppm the planetary mean temperature will rise above 2 degrees Celsius by the middle of the century. With this temperature increase, positive feedbacks will be engaged that push up CO2 levels to 750 ppm. At this concentration, mammalian life on the planet is largely unviable. Therefore, it is critical that the global temperature not rise above 2 degrees Celsius.

It is doubtful that any nation would seek its own geoengineered solution to global warming, especially since the countries most likely to be the first ones most impacted are in the worst position to take such actions, e.g. countries in Africa, etc. There is a UN treaty that prohibits weather modification for hostile reasons, but it has never been tested and how do you define hostile?

An internationally approved approach would be the most likely way such a response is made. A single nation with access to naval rockets could carry out the sulfate aerosol work, but the other most likely schemes would by necessity involve more and more multilateral support. The Bush Administration did consider the floating plastic island as an alternative to Kyoto in the late summer of 2001, but decided instead to do neither. It would have been interesting to see how that one would have been sold to the UN or the UNFCC.

There was a consensus on Kyoto as well as the much smaller in scope Montreal Accords on CFC reduction. Most of the worldâ??s nations have ratified the Kyoto Protocol, although only around 40 are actually required to do anything and only a few of them are on target to meet their requirements. The geoengineering schemes wouldnâ??t require emission reductions, so countries like the U.S. and Australia couldnâ??t argue that it would harm their economies at least directly. Bottom line: international agreements have been reached in the past on global environmental issues and will be reached in the future.

The space reflector would not be noticeable at the surface and the amount of sunlight reduced would not have any impact on photosynthesis. The arguments against it are not that it would have potentially harmful side effects. Instead, it is its infeasibility that renders it a dead end option in 2006 and probably 2050 also.

We envisioned a future Kyoto-like treaty to provide the mechanism for financing and operating the desert cover. Because land in a number of different nations would be involved, their cooperation would also be required.

That said, if nothing gets accomplished internationally over the next, say 25 years and things start to go bad in China or Russia or some other place with the resources to take unilateral action, yes, then I believe that is a possibility.

Dr. Crutzenâ??s plan may be the first test of this theory of geoengineering policy, since before full-scale implementation would come the field trials. But I wouldnâ??t buy any tickets to the first launch just yet.

We do know that around 900 AD until around 1400 AD we had a large warm spell on the planet. We don’t really need any science to know this for viking history tell us it was warm enough in Greenland to support 10,000 people in an agricultural society.

… archaeologists guess that the population may have risen to a peak of about 5,000.

This website (which is a great read!) gives a host of possible reasons (including climate change, conflict with the Inuit, raids by Basque pirates, heavy taxes and tithes) that may have contributed to the decline of Greenland settlements. You also state

We also know that it was too cold to live there anymore and still is.

Yet there *are* people living there, and have been continuously since the Norse deserted the place: the Inuit. In fact the Inuit were well-adapted to life in an icy environment; today they are threatened by the *warming* of the arctic region.

You wonder

History says that higher temperatures will make the deserts bloom and the steppes lush; why don’t our models?

I’m not a paleoclimate expert, so I can’t comment intelligently on the claim that historically, warmer climate has made the deserts bloom and the steppes lush. But if I accept that as true (for the sake of argument), at least two differences are clear: 1. Past warmings were far more gradual, causing less chaos for ecosystems and giving them much more time to adapt; 2. Past warm periods didn’t have the exaggerated CO2 concentrations we’re seeing today, so were free of problems such as ocean acidification. Perhaps that’s why the models don’t show a lush, friendly environment heading our way.

“Those that manifest strong or unequivocal opposition to geoengineering…underestimate the serious danger our planet is facing. …positive feedbacks will be engaged that push up CO2 levels to 750 ppm. At this concentration, mammalian life on the planet is largely unviable.”

George, I agree that, if ‘we’ do not do something soon, humans and many other species will vanish. Perhaps we are already committed to that; the evidence is not yet conclusive. The reason I oppose geoengineering is because it is not a root cause solution, and I believe we must, as a species, finally grow up a bit and accept responsibility for being the root cause.

I do not trust us to geoengineer while also fixing the root cause as quickly as possible. We are still in denial about that! It seems more likely that we will use geoengineering to continue as we have been, or at best, slowly, slowly bribe GM to convert to ethanol.

If you ask me if humanity is worth saving at any cost (and I don’t just, or primarily, mean economic), I would say no. Geoengineering will simply allow us to do more damage to poorer countries and other species, while prolonging the run of the wealthier countries.

“…. Three years after the eruption, nearly all of the Mt. Pinatubo aerosols were gone.

“One disturbing point … is that it appears to take much longer for aerosols to be removed from polar regions than from tropical regions. The polar regions, particularly Antarctica, are particularly susceptible to major drops in stratospheric ozone.”

The one-time eruption of Pinatubo, plus a couple of Southern Hemisphere volcanoes, was enough to counterbalance about one degree Fahrenheit of warming — and produce the worst ozone depletion. Bad tradeoff, eh?

“The Pinatubo climate forcing was stronger than the opposing, warming effects of either the El NiÃ±o event or anthropogenic greenhouse gases in the period 1991-1993.

“As a result of the high stratospheric aerosol loading, mid-latitude ozone concentrations reached their lowest recorded levels during 1992-1993. Startling decreases in ozone abundance and in the rates of ozone destruction were also observed over Antarctica in 1991 and 1992. … The southern hemisphere “ozone hole” increased in 1992 to an unprecedented 27×10 km in size, and depletion rates were observed to be faster than ever before recorded … raising concern about the amount of biologically destructive ultraviolet radiation reaching the earth’s surface….”

Most of the sulfate does eventually drop out — most of it in the oceans.
Increasing the acidification of the upper ocean even faster.

Bad idea, even assuming a launching device capable of putting that amount of sulfate into the stratosphere every few years.

Geo-engineering as an excuse to continue to burn fossil fuels is wholly unsustainable. However, exploitation of some novel or unused natural mechanisms, husbanded on a large scale, may enable us to intervene to mitigate and maybe even reduce atmospheric CO2 content.

Now I wondered recently at reports of an oceanic algal bloom so large it could be seen from space. As I understand it, blue-green algae absorb CO2, or in this case maybe make use of the carbon in Carbonic acid in solution, and photosynthesize to produce biomass. If this is the case, would this also not be a counter-acidification process for the oceans, and could the algal blooms be harvested, ( e.g. by suction dredger like an oil-spill recovery tanker) and processed to provide biofuel/ soil conditioner/ some other useful product that might retain the Carbon out of atmosphere for a longer period, even if not permanently sequestered?

I’m sure there are several good reasons why not, but I thought I’d ask.

I am a geologist, and have been interested in some of the LANL work on CO2 stripping.

The basic idea goes like this: Use solar or wind power to force ambient atmosphere through a solution containing high concentrations of dissolved CaO, MgO, FeO, MnO or other metal oxide. Bubbling CO2-rich atmosphere through such a solution allows the CO2 to combine with the metal oxide to form a carbonate (CaCO3 – calcite, MgCO3 – Magnesite, FeCO3 – Siderite, MnCo3 – Rhodochrosite). The carbonate minerals precipitate out of the solution as a stable or metastable solid that can be formed into blocks, buried, used for building, or whatever.

There are, of course, problems: Where to get sufficient volumes of the metal oxides (they are fairly abundant in Ophiolite deposits and other minerals (Limonite, Hematite, Magnetite, Manganite, Peridotite/Olivine, Serpentinite, and etc), how to create such oxides from existing mineral deposits (requiring energy), how to force enough atmosphere through such a system (requiring energy), and how to deal with CO2 depleted atmosphere if it reaches high-enough concentrations locally to disrupt the ecological balance.

However, it seems to me that solar furnaces, wind or water generation for both the refining of the metal oxides and the forcing of atmosphere through the solution are definite possibilities.

The real problem is how to make such an effort work on a scale large enough to actually impact the atmospheric CO2 concentration.

There is a real problem with conservation alone as a “fix” to global warming: The current concentrations are essentially too high for the current climate system to remain stable, and even if humans stopped putting ANY CO2 into the atmosphere tomorrow, those concentrations would not begin to even drop for 100 or more years….that is assuming that the current levels have not reached the point where a new climate regime is already in the works and what we are seeing now is just the transition period from one stable state to a new stable state.

Conservation and prevention must remain key components of any solution to the problem, but I think that one thing that the “terraformers” have going for them is the basic idea that remediation is, indeed, a critical component of any workable solution.

Re # 118 In order to stimulate phytoplankton (blue greens, diatoms, or whatever) in the ocean to take up significant amounts of atmospheric CO2, you have to provide one or more limiting nutrients – iron is in short supply in large areas of the Southern Ocean, and adding iron does seem to stimulate phytoplankton blooms (see refs cited below). However, the key is the get the phytoplankton to sink to the bottom of the ocean without being eaten or decomposed. Harvesting the biomass and using it on land will release the CO2 back into the atmosphere (due to decomposition or combustion).

Here is an abstract of a brief review of this topic:

Will Ocean Fertilization Work?
Ken O. Buesseler and Philip W. Boyd
Science 4 April 2003:
Vol. 300. no. 5616, pp. 67 – 68http://www.sciencemag.org/cgi/content/summary/300/5616/67
“Iron fertilization of the ocean is widely discussed as a possible strategy for extracting CO2 from the atmosphere. In their Perspective, Buesseler and Boyd analyze the results from recent fertilization experiments in the Southern Ocean. They conclude that sequestration of 30% of the carbon released annually as a result of human activities would require a region more than an order of magnitude larger than the entire area of the Southern Ocean. Iron fertilization may not be a commercially attractive option if impacts on sequestration are as low as observed to date.”

The April 16, 2004 issue of Science contained three articles on fertilizing the Southern Ocean with iron to stimulate CO2 uptake – here is a link to a commentary on those articles:

One of those articles (Buesseler et al. pp. 414 – 417)
concluded that “The flux of carbon was similar in magnitude to that of natural blooms in the Southern Ocean and thus small relative to global carbon budgets and proposed geoengineering plans to sequester atmospheric carbon dioxide in the deep sea.”http://www.sciencemag.org/cgi/content/short/304/5669/414

One major concern (in my mind, at least) is that we have very little information about how ocean fertilization experiments impact oceanic food webs. I recall reading a paper a few years ago (I don’t have the ref. handy, but it may have been in Physiological Zoology – now called Physiological and Biochemical Zoology) providing some evidence that phytoplankton blooms in the Southern Ocean stimulate krill populations, which in turn are eaten by marine mammals – the latter exhale the CO2 back into the atmoshpere, resulting (apparently) in very little CO2 sequestration.

Re: # 120 “This is seemingly the key divide between those that are open to geoengineering and those that are not. The former are committed to humanity’s survival.”

If George Gonzalez is implying that those who are opposed to geo-engineering are somehow not (or less) committed to humanity’s survival, I say, HOGWASH!!!

The first part may sound complicated if you do not like math, so feel free to skip to the second. I have tried to simplify it, but I have not slept so sorry.

FIRST:

Suppose that the temperature of the earth depends on n factors. The collection of the n factors + temperature is what we call “climate.” If you change one of the factors (like, adding CO2) and live all others unchanged, you change the temperature, thus, you have changed climate. Now, if you change one factor, and then change another factor to counterbalance the change in temperature, you may end up with no change in temperature. An example would be pumping CO2 and pumping sulfates. This would be a geo-engineering solution!

Do you see the problem with these geo-engineering solutions? Basically, you end up with the same temperature, but your CLIMATE has changed. Recall that climate is the collection of ALL n factors PLUS temperature. Thus, if you change any factor there are two ways to conserve temperature. One is to take the factor you changed and bring it back to normal. The other is to change some other factor. The first conserves climate, the latter does not.

Basically, just think of climate as a point in some mapping in (n+1) dimensional space. If you change any one of the inputs the other will have to adjust.

SECOND:

An example of the above can be drawn from economics. When you have an economic recession that is induced by the supply side, the level of output (GDP) will drop and the Price level (the average price in the economy) will rise. In order to counteract this, policy maker may want to increase the money supply (print more money, lower interest rates, etc.) This encourages economic activity and the level of output goes back to normal (GDP) BUT the price rises even further. Ladies and gentleman, we have some inflation.

In terms of our planet inflation may be anything. Saltier seas that grow nothing.

Finally, I assume no other interactions among the variables. In reality they do interact. So saltier seas imply no plankton which implies no fish. Then bacteria come in to eat all the dead stuff and these bacteria may bring disease.

It sucks to know that if you are in the developing world you will be punished for the actions of the more developed countries. Africa accounts for about 5% of CO2 emissions. The US, with less than 5% of the world population, accounts for over 25% of CO2 emissions. Furthermore, the changes imposed by global warming may render agricultural production impossible in many of the now-tropical climates. If you thought you were dependant on foreign industrial goods, wait until you buy food from them (if food is not scarce and can be sold…) then you will know what dependancy means.

This is simply because the man in charge gains from the burning of fossil fuels. So sad. We choose to do nothing about it and entertain ourselves watching CNN. Look, they caught a guy with a big beared! My life will improve! Oh my god, its N. Korea! Ahhh!

If a chemical system at equilibrium experiences a change in concentration, temperature, or total pressure, the equilibrium will shift in order to minimize that change.

I love that statement because you can apply it to other sciences as well (I apply it to economics all the time.) Now, lets keep it in a chemical context. The earth is a collection of chemical systems that form one giant system. Lets rewrite the statement with this in mind:

If a chemical system (the earth) at equilibrium (the climate as we know it) experiences a change in concentration (CO2 is becoming more concentrated), temperature, or total pressure, the equilibrium will shift in order to minimize that change.

Chemically, if you have A + B < ==> C + D at equilibrium, and then the playground bully adds more B, the reaction will move to counteract this change. Lets look at it in chronological order. Here, the numbers in parentheses will indicate possible concentrations:

A(10) + B(10) < ==> C(10) + D(10)

1) add B

A(10) + B(20) < ==> C(10) + D(10)

2) System reacts and new equilibrium is reached

A(5) + B(15) < ==> C(15) + D(15)

Now, what this means in our planetary example is the following. If you dump more CO2 the earth will do stuff to get rid of it. Stuff includes diluting it into the ocean, creating more biomass (biomass removes CO2) or killing CO2 producing organisms, like fish, cows, and , um… humans. That does not mean that we are going to die, it simply means that all those things that are bad for us will become a much more common.

There is something we can do though. If we limit our artificial (cars, factories, basically hydrocarbon burning) inputs of CO2, then we help earth in the regulating process, and those forces design to wipe us out may not come out so strong… So instead of 30,000 less humans we can have one less hydrocarbon based electrical plant.

” There is something we can do though. If we limit our artificial (cars, factories, basically hydrocarbon burning) inputs of CO2, then we help earth in the regulating process, and those forces design to wipe us out may not come out so strong… So instead of 30,000 less humans we can have one less hydrocarbon based electrical plant.”

I just returned from my lunch break at work. I’m in the Miami area and we are having a light on and off rain. I went to a fast food restaurant and parked in a completely empty parking lot. I walked into the restaurant to order my food for take out. While there I observed a long line of vehicles, most of them of the large SUV type in the drive through lane with their engines idling, AC’s running of course, while they waited their turn at the take out window.

I am the only one thinks we need to change this kind of behavior? If so then how do we start the process of education?

Ironically I was in and out of the restaurant with my food more quickly than most of the people still waiting in their cars in line. I guess we really are going to need all the geo-engineering schemes we can come up with so we can continue to lead this wonderful lifestyle.

#125 You state, “This is simply because the man in charge gains from the burning of fossil fuels. ”

Now that’s what I call a simplification. Global climate change is due solely to a single person. Will you kindly identify “the man in charge” and quantify with numerical evidence what, how much, and how he “gains”?

Ocean reflectors are a practial and safe geoengineering proposal. I guess that current GHG forcing could be offset by covering between 1-5% of the world’s tropical oceans with floating white plastic reflectors. Make them cheap, durable and resistant to discoloration from algae. Imagine something similar to a white plastic milk bottle. They could be deployed economically by fencing large areas of ocean with floating nets and then shipping the reflectors direct from the factory to the site. The density of reflectors could be restricted to allow life to continue below.

A positive side effect of this scheme would be to lower the local water temperature and help to mitigate hurricanes. It would be ideal to deploy off the east coast of Florida. If undesirable side effects were discovered, the reflectors could be simply removed by dragging in the nets.

Does anyone know of research papers examining this concept? It is mentioned briefly in the NY times article. Determining the required surface area should be relatively easy using a global climate model.

I think he meant “The Man” ;-) And now that someone has broached the topic, I thought I throw out my own crackpot piece of paranoia about The Man…

Some time after the start of Gulf War II, it occurred to me that maybe the whole point was to reduce the world oil supply and starve China’s growth since China is a leading competitor in the impending “New American Century”. On the face of it, this seems inept because China has plenty of coal. But if you add in the fact of AGW and the resulting rather nasty consequences for China (flooding of costal cities, disruption of agriculture and drying up of the Tibetan plateau watersheds) maybe this was the intended long term result? Not to mention the secondary results of similar effects upon China’s populous neighbours (i.e. India and Indochina) resulting in war and massive refugee migration?

OK, that is enough darkness for one day. Time to take my happy pills again…

RE: #131, I think I know the man in charge. His name is Wally, or something like that. He and his 299.999 million neighbors are, in fact, all in charge. They share something else in common; they are all consumers residing in the U.S.

I blame environmentalists (my peer group) for putting all the focus on the corporate “man” and thus letting us consumers off the hook. The campaign has a simple message to policy makers — make corporations clean up their powerplants; make them sell us high MGP, compact cars; make them build us 1200 sq.ft., air tight homes; and, make us ride their trains and buses. Does that sound familiar? Does that seem to be working? Do Wally and his neighbors approve of those goals?

My family outvotes me at the air conditioner thermostat and a few other household matters that will cut down our energy consumption. It is tough being green in a consumer world.

Though in general I hold Groucho Marx’s views with regards to joining clubs; I have to say John, welcome to the club. Especially since Wally’s club doesn’t want us around with inconvenient facts and suggestions about turning down the thermostat. Then again Groucho also said ” I have a mind to join a club and beat you over the head with it.”

The U.S. is the largest absolute and per capita emitter of the key climate change gas: carbon dioxide. This is because U.S. urban zones are by far the most sprawled in the world. Urban sprawl results in greater energy demand for commuting and heating/cooling/powering larger homes in suburban areas.

The sprawling of our urban regions was prompted by the nation’s political and economic elite. Most obviously, through the policies of the Federal Housing Authority (FHA), which would only guarantee the mortgages of homes on the urban periphery. The specific economic/political benefit of urban sprawl is that it greatly expands demand for automobiles and for those consumer durables that fill those large home in suburban areas.

Yes, I blame “the man” for this. Number one, he DOES benefit from oil. The top officials working for him also worked for oil companies. Their environmentalist advisor “resign” after a memo was published showing how he was ordered to alter the reports from the EPA, now that man resigned to spend more time with his family… the nex day he was hired by Exxon.

Now, I blame the man not because he is trying to make a living working for this companies. Dont get me wrong, I dont care about big business making it large (lets just say that I have drinked Star$ coffee) but I do believe in people doing their jobs. That man’s job, right now, is NOT for the oil business, it is for the American people. His top priorety should not be to gather more oil sources for his business, it should be to make the US people less dependant on oil. People respond to incentives. He has not provided the right incentives to cause great change. That is why we ave those SUVs. Make them pay a tax that reflects the damage they are creating! China has about 15% of the world s population, they produce 13% of Carbon Dioxide, the US has 5% (at most) and they produce 30% of the Carbon Dioxide. The numbers of China may seem ok, but the entire African continent produces less than 10% of emissions.

So, this is a phenomenon that has been going on for over a century. Ok, so in that case I should not blame “the man.” But today, his decisions do have enough force so that if he were to change them, he could probably improve the situation more than any one can.

#1 Carbon taxes. A high tax for business, drivers, and everyone who directly or indirectly uses carbon based fuels will cause good CHANGE. This tax can be accompanied by lower taxes in other areas (for example, a slightly lower income tax.)

#2. The US is the major economy in the world. Very competitive. “The man” took them out of the Kyoto Protocol initiative as soon as he became “the man.” This means that, if the other countries in the protocol went through with the reduction of emissions, they would lose big time. Basically, reducing emissions costs money and if, say, Germany decided to cut emissions while the US does not, their industries lose their competitive edge. The US would be able to provide lower prices for equal products.

Thus, the decison of “the man” to drop out of the Kyoto agreement, has led to countries like Germany to force very poor emissions standards in Europe. Thus, the decions of “the man’ are also affecting the way other countries behave.

#3 The US is also a technology exporter. Lets face it, very few countires produce industrial technologies. If the US industry continues to be oil dependant, the technologies they produce will be guided towards machines that ran on oil. Now, this technologies are placed on CAPITAL that uses oil. This capital is either installed in US businesses or exported and used in poorer countries that cannot developed such technologies. How is this a problem? Well, suppose that tomorrow “the man” decided to change or the US people changed “the man” altogether. New laws are passed. Well, all the “CAPITAL” is expensive. You cant just throw it away. So, you are left with a bunch of CAPITAL that operates “the old way” and until it loses its use, there will be no cheap way to change it. An example of this (I recently read it on my theory of econ growth textbook which is at home, —#131 if you want the numbers, I will look for them specially for you!) was after the development of a new furnace method to make iron. Japan (or I think it may have been China) adopted the technology very quickly about 10 years. On the other hand, the US (ironically the developer of the technology) took about 50 years to adopt it. Reason (this will make the irony less ironical..): China had no furnaces to replace, they were a poorer nation, so all the new furnaces they were making had the technology. The US on the other hand, had a bunch of furnaces (rich nation, one of the major exporters) that used the old technology. Replacing them was too costly, so they had to wait until the furnaces got very old and had to be replaced.

Now, in poorer countries it takes longer to replace capital (basically, they use it until the wheels fall off. In Nicaragua, I have seen them use buses that were used in Germany before 1945. Have you ever seen a Lada, go to Nicaragua. A better example is Cuba, it looks like the 1950s over there.) So, expect some long term effects form this capital that is being produce right now. Thanks to “the man.”

This are three reasons on the top of my hand why “the man” could make a big difference but does not. I hope its enough but if anyone is not yet convinced I’ll write a few more.

Also, by the way, a lot of US cities today are designed so that you cant get around without a car. I do not include this in my last post because it is really hard to find good evidence on it, and because I cannot blame “the man” for this. The best evidence is to live in one. Try to walk or bike somewhere… Luckly I live in a smaller one so this is not the case for me right now. I recently took a trip thought…wow! This is the hardest form of capital to change.

This should be a warning for developing countries. They should city plan taking this into account. My mom recently visited a country in an other continent and mentioned that most people got around in bikes. Good to know.

2. Over geologic time, the dominant CO2 buffer is the carbonate/silicate cycle. How there been any geoengineering proposals to increase chemical weathering rates of basalt in tropical areas? It seems like an obvious course of action would be to devegetate such areas, as this will allow increased soil erosion and mass wasting, so that the bedrock is more exposed. You could even plant bananas on the denuded areas, to recoup some of the economic costs.

Now, about devegetation. The quantity of CO2 released will bu much great. In addition, trees cooling action does not only come from their containment of CO2, but also from their containment of energy from the sun, water retension (less water vapour in the air is good, since water in gas form is a greenhouse gas.) Many other negatives on that but the biggest one will be depriving of life to animals and plants. Besides, who wants to live in a place with no vegetation…

At least here in Aus, trees increase humidity, not decrease it, because they store and then transpire water that would otherwise run off.
As for the “lag time” it takes for weathering to remove the vegitation’s equivalent of CO2, I have no idea what that would be. But if you simplify wood to C6H10O5 (a generic, infinite starch), then you need 14 times the mass of basalt (at 15% CaO) to compensate. so as long as your basalt is more than a few meters thick, weathering should provide a larger eventual sink than maintaning vegitation. On the other hand, I suppose that weathering a meter or 2 of bedrock probably takes > a century.

An earlier comment called for peer-reviewed assessment of the energy cost of the entire nuclear power process. The UK has appointed a Sustainable Development Commission to dig up such assessments of how much CO2 is emitted, and in section 4.4 of their Paper 2: Reducing CO2 emissions – nuclear and the alternatives they do:

The average amount of CO2 emitted by nuclear power in Western Europe is estimated at 16tCO2/MWh for a Pressurised Light Water Reactor (PWR)… several sources have made estimates around this figure… By contrast, coal emits around 891tCO2/MWh while gas is around 356tCO2/MWh…

(Section 4.7)

… in a low carbon economy, the indirect emissions from nuclear power, along with other low carbon technologies,would be substantially reduced.

Unless I have completely missed the point comparing CO2 emissions for coal, gas and nuclear powered disregards the embedded energy requirements that go into getting a nuclear power plant to the stage where it is producing energy and not emitting any CO2.

I seems to me that the economics at least are pointing to wind and solar being much more cost effective with lower embedded energy requirements than nuclear power plants.

Total life cycle energy costs calculations are both daunting and require assumptions. Anyone wishing to bend the result in a particular way can simply make the needed assumptions. This is as true of coal, oil and gas as nuclear. For example, while it is true that construction energy expenditures are higher for nuclear than coal, transportation and mining costs are much higher for coal, and then of course, depending on the decision of what to do with the slag heap,
coal ash “decommisioning” costs can also be high.

Most of the energy costs associated with nuclear can be generated thru electrical power which, in turn can be generated by nuclear plants (e.g. isotope separation). The US isotope separation plants were built to supply naval reactors and weapons, thus they are over-built for nuclear power generation. Life cycle energy costs are much better captured by the experience in France and Japan, which a) don’t support a huge nuclear military complex, b) have standard designs c) reprocess.

The quick synopsis is that the percent of output used as input for energy is about 2% for nuclear with centrifuge isotope separation and 5% with gaseous diffusion, coal varies between 2 and 6%, gas is about 15% because of transportation costs,

What is the ‘cost’ of disposing of nuclear waste ‘safely’? Currrently, I imagine costing models either ignore the problem or make convenient assumptions and pass it on to someone else (future generations, taxpayers). I doubt anyone counts it as infinite, which seems the most justified at the moment.

In addition, do current costing models include the many, many non-economic costs? This includes everything from aesthetics to safety to environmental impact to the unintended consequences. (Eg: Building roads enables and causes the expansion of the number of cars. Did it also lead to the decline of rail and the growth of long-distance trucking? What will building nuke plants cause?)

Passive solar heat and hot water seem feasible, non-geoengineering goals for most new residential construction. A few changes in building codes would do more – much more safely and sustainably – than any geoengineering project.

“If I convince you to retrofit your house for energy efficiency, you can save maybe 50 per cent, but you have to do this approach person by person by person. Getting the building code changed, on the other hand, changes every single new house. The costs wouldnâ��t be noticeable. … say itâ��s a couple of per cent, are you going to see that? The bathroom fixtures cost more than that. If the building code changes on every single house, or if you canâ��t sell your house without putting a label on the door and showing what the operating costs are, and having some minimal retrofits done, then the whole market changes.”

“On what keeps urban planners up at night:

“…Almost every major city around the world is going to double in size in the next 45 years, and we have got to get some of that new construction done right or we get into way more expensive retrofits after more damage is done.”

It seems a typical form of short-term thinking, when people try to solve one problem by creating another. Maybe sulphate aerosols can cool down the climate again, but what are the consequences ? How will they interact with other substances, how much sunlight will be blocked and where ? Maybe we’ll just create another and even bigger problem with them.
The only sensible thing to do is change our way of living and finally realise that we can’t go on pretending to be the only important species on earth, realise we have an obligation to other life forms and our children to protect the planet, but that will cost, and that’s where the problem really lies, men has but one deity and that is the coin.

First let’s get the “we’re playing God” idea out of the way. We’ve been doing so, on a global as well as local scale, since we started making conscious decisions. We took it to a new level when we first started intentionally burning carbon. Now it’s time to pay the piper. It seems unlikely we’ll make enough individual and voluntary lifestyle changes in time. And the bigger question is, would we do it to support the status quo, the present economic system, efforts toward American Empire, or civilization and many species, including Homo Sapiens? (I hesitate to call us “human”, whom I’d think would posess more community spirit and forethought.)

On the other hand, science has always been “fraught with uncertainties” (#10), but without it, we’d still be very primitive hunters and gatherers. I think we’ve made some gains over that.

Intentional global dimming is a necessarily limited and short-term solution, but one that could give us time for others. It’s also one that would be slow to “backfire”, but easy to correct excesses quickly. If we saw changes in the three days after 9/11, I’m not worried about long-term effects. Time is rather critical, because oil depletion and other factors might suddenly and drasticallly reduce all our efforts, as well as our present cooling pollution, without being enough to stop self-reinforcing natural effects already in the works. It seems not so long ago we were concerned about falling temperatures, it turns out, due to air pollution. Are there maybe other products besides sulphates that might also work?

An object in space, orbiting either the earth or sun, will only spend a small amount of time between the two.

The second part of the geo-engineering solution I see is mechanical CO2 sequestration from power plant emissions, maybe eventually from the air. There’s talk about where to store it, but apparently not about how to separate it from the nitrogen. Does anyone know of a link on this? I have my own ideas about it, for those who understand such things. If we could get this going, we could regulate global temperatures, maybe locally also, to our liking. Then we could wait for fossil fuel depletion, or maybe uranium depletion, to give us a more dependable solution.

Legal liabilities are a problem of our laws, where we punish those who harm us, but aren’t so willing about helping those who help us.